thejum57 Posted January 10, 2015 Share Posted January 10, 2015 My truck only overheats when it is frigid cold. It's happened 3 times now over the past 5 years. No one has a clue why, they just "fix" the end result....broken hose, popped out freeze plug etc. It just did it again. Temps here in MA were -0, after about 15 min driving to work the light came on. Drove it back home, when I parked it, it was boiling. Antifreeze sprayed all over. Today I checked all the hoses, freeze plugs, all good. Started it and let it run to see if I could see antifreeze coming out....zero. Drove it a little, let it sit running...zero. Only cold air coming from the heater / defrost, it does give heat, not a lot but enough to keep me warm usually. When I shut it off, the top hose was hot, and gurgling. the heater hose were slightly warm, the bottom hose was cold. Also I can squeeze the top hose, running or not easily. Shouldn't the hoses give some resistance cause they are full of fluid? It's the 2.5 engine with 124,000 on it. Normally it runs great, gives fair / good heat 18 mpg. Could this be as simple stupid as the thermostat? All summer it runs fine, never got hot. Thanks Link to comment Share on other sites More sharing options...
Dadinator Posted January 11, 2015 Share Posted January 11, 2015 Frozen fluid will cause this. Keeps it from circulating and therefore overheats in other areas. Check you fluid. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 11, 2015 Share Posted January 11, 2015 I think it's time to swap in a full gauge cluster and dump the idiot lights. With a gauge you will be able to see exactly what the engine temperature is doing to diagnose it better. I'd also pick up an antifreeze tester, use it, and replace the thermostat with a Mopar stat with the jiggle pin. Link to comment Share on other sites More sharing options...
yxmj Posted January 11, 2015 Share Posted January 11, 2015 What is the ratio of anti freeze you are using......maybe it is not enough for the temp. Run a 50/50 mix and you will be safe. There are testers avalible to check your existing if you need to. Link to comment Share on other sites More sharing options...
jimoshel Posted January 11, 2015 Share Posted January 11, 2015 As stated above. Get a gauge, even if it's a after market under the dash bolt in. Drain and replace the coolant with a 50/50 anti freeze, water. Link to comment Share on other sites More sharing options...
thejum57 Posted January 13, 2015 Author Share Posted January 13, 2015 I have always run really heavy on the antifreeze, close to 100%. I put in a new thermostat just because who knows when it was last replaced. Now it dribbles and the "heat" comes out cold....yea!!! Also there was a knockout part of the gasket that I popped out because there is an opening in the block that matches up. Going to remove and add some Permatex to the mix before re installing. By the way I did run the heat when I started it after thermostat replacement and added straight antifreeze until it was full. :doh: Link to comment Share on other sites More sharing options...
91Pioneer Posted January 13, 2015 Share Posted January 13, 2015 I have always run really heavy on the antifreeze, close to 100%. 70% antifreeze max, after that you are actually losing protection. Link to comment Share on other sites More sharing options...
gogmorgo Posted January 13, 2015 Share Posted January 13, 2015 :doh: Well now we know what's causing your issues... 100% ethylene glycol (EG) freezes at around 10°F. Given that you said it hit 0, this isn't enough for you. The other issue you have is that EG only has about half the heat capacity as water, so it won't properly cool your motor, or heat your interior. Adding water to EG (usually I think of this the other way around!) will lower the freezing point. The lowest freezing point you can get is around -60°F at a 70% EG mixture. The usual recommended mix is 50% EG, which freezes around -35°F. Now, where XYMJ, 91Pioneer, and I live, it sometimes drops below -40, so this isn't enough for us. For ease of measurement, I run approximately 66% EG (2:1 EG:H2O) but 60% is more than acceptable here. It's also not uncommon for people here to run 50/50 here anyhow... heated garages are reasonably common, and everyone has a block heater. Now, I don't know exactly where you live or what your climate is like, but given that Boston's absolute record low is -18°F, I'd say a 50% EG mix is more than enough for you. TL/DR; 50% antifreeze = good. 100% antifreeze = BAD. Don't do it! Link to comment Share on other sites More sharing options...
Dando Posted January 13, 2015 Share Posted January 13, 2015 Link to comment Share on other sites More sharing options...
thejum57 Posted January 15, 2015 Author Share Posted January 15, 2015 You guys rock. This weekend , I am draining the system, and re-installing the thermostat with some Permatex... there was a tiny bubbling leak at the top of the thermostat housing. Then I will add around a 50/50 mix this time. One more question, the owner's manual says the 2.5 takes 10 qts / 8.3 qts...that's how it reads, which one do I follow? I'm thinking about 5 quarts of antifreeze, thin fill with water. Thanks! Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 15, 2015 Share Posted January 15, 2015 I always premix the antifreeze and distilled water in the bottles, then fill, burp, top off, burb, etc. until it's done. That way you know it's a true 50/50 mix throughout. Link to comment Share on other sites More sharing options...
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